The invention relates to a method and apparatus for winding an advancing yarn to form a yarn package.
When winding a continuously advancing yarn to form a yarn package with a contact roll lying with a contact force against the circumference of the package, the increase of the package diameter is made possible by a deflection of the package mounted on the winding spindle support or by a deflection of the contact roll. In this process, the contact remains between the package and the contact roll, so as to generate a predetermined contact force on the package surface.
EP 0 374 536 and corresponding U.S. Pat. No. 5,029,762 disclose a yarn winding machine, wherein the deflection of the winding spindle supporting the package is controlled during the winding cycle as a function of the position of the contact roll. In so doing, the lifting movement of the contact roll is detected by a sensor. To this end, the contact roll is mounted for movement in such a manner that it can perform a lifting movement radially to the package being wound. Once the contact roll leaves a desired position, the sensor generates a signal and supplies same to a controller. The controller controls the drive of a spindle support mounting the winding spindle, so that the package performs a deflection until the contact roll reaches again its desired range. During this two-position control, the spindle support is moved at a constant speed. This results in that relatively significant controlling efforts must be made in particular at the beginning of the winding cycle. In addition, the stepwise drive control of the spindle support leads to an unavoidable change in the contact force between the package and the contact roll.
It is accordingly an object of the invention to further develop a method of the initially described kind as well as a winding machine for winding a continuously advancing yarn such that the center distance between the contact roll and the package is changed substantially proportionately to the increasing diameter, while keeping control efforts at a minimum.